Using the Basic Components › Multiple Volume Data Set Recall Support

Multiple Volume Data Set Recall Support

When an application opens a data set that resides on a CA Vtape Virtual Volume, CA Vtape checks to see if the volume being mounted is in cache. If the volume is not in cache, it is recalled.

When an application is reading a multiple CA Vtape Virtual Volume data set, a recall may be generated for each Virtual Volume in the chain as each volume is mounted. This results in a series of short delays after each volume is mounted for the volume to be recalled.

These delays can be eliminated if CA 1 r11.5 SP5 or above or CA TLMS r11.5 SP3 or above is installed. With this support in place, when an application opens the first volume of a multiple CA Vtape Virtual Volume data set that is not in cache, a recall request will be generated for the first volume and the CA tape management system will check to see if the next two Virtual Volumes in the chain are in cache. If the volumes are not in cache, recall requests will be generated for them. When the second volume is mounted, the tape management system will check to see if volumes three and four are in cache. If not, recall requests will be generated for them.

Since the application will no longer experience the series of short delays, job run-times will be reduced.